Replace also _PyObject_HashFast() with PyObject_Hash()
in _collections._count_elements().
Rename _PyObject_HashFast() to _PyObject_HashDictKey(),
and mark it as Py_ALWAYS_INLINE.
Only use _PyObject_HashDictKey() on dictionaries.
Since the recursion guard tracks real C-stack bounds (gh-91079), this test
asserts that 500k nesting levels overflow the stack margin. On a 64 MiB stack
(some Nix build envs use one that large), the optimized interpreter uses ~160
bytes/level (raises at ~420k levels) so the assertion holds with only ~16%
margin; the PGO *instrumented* stage inlines less, its per-level scanner frames
are smaller, and the 500k-deep decode completes -- "RecursionError not raised"
fails the profile run and aborts `make profile-opt`. Upstream's
skip_if_unlimited_stack_size (gh-143460) only covers RLIM_INFINITY, not
large-finite stacks like ours.
We could also keep playing whack a mole and raise the 500k to a much larger
number... but there's little value in PGO training on this test anyways.
The standard says that a call to `memcpy` must pass a valid source and
destination pointer even if the size is 0, so we must avoid calling
`memcpy` when our source pointer is NULL. If we don't, an optimizing
compiler can decide that the pointer must be non-NULL based on the
presence of UB, and optimize out checks for null pointers.
Specifically, note that the standard says:
Where an argument declared as size_t n specifies the length of the
array for a function, n can have the value zero on a call to that
function. Unless explicitly stated otherwise in the description of
a particular function in this subclause, pointer arguments on such
a call shall still have valid values, as described in 7.1.4.
And section 7.1.4 says:
If an argument to a function has an invalid value (such as a value
outside the domain of the function, or a pointer outside the address
space of the program, or a null pointer, or a pointer to
non-modifiable storage when the corresponding parameter is not
const-qualified) or a type (after default argument promotion) not
expected by a function with a variable number of arguments, the
behavior is undefined.
The specification for `memcpy` doesn't state that it's allowed to be
called with null pointers, and Linux's `/usr/include/string.h` declares
`memcpy` as `__nonnull ((1, 2))`.
Append parsed values to the result list with _PyList_AppendTakeRef and
insert key/value pairs with _PyDict_SetItem_Take2, which take ownership of
the references instead of incref-ing on insert and then decref-ing the
local. This removes a reference-count round-trip per element (and, on the
free-threaded build, a per-append lock).
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
* Py_FatalError() no longer calls _PyFaulthandler_Fini() if it
doesn't hold the GIL.
* Skip test_faulthandler tests raising signals if run with UBSan.
* Enable test_faulthandler in GitHub Action "Reusable Sanitizer".
If "import encodings" fails at Python startup, dump the Python path
configuration to help users debugging their configuration. The
encodings module is the first module imported during Python startup.
JasonMendoza2008